The present invention relates to a process for hydroconversion of light and heavy feedstock, especially heavy naphtha feedstock, to a catalyst for use in hydroconversion processes with a feedstock having sulfur and nitrogen contaminants and to a process for providing such a catalyst.
Light naphtha feedstock can be treated by hydroconversion to produce premium isomerized light gasoline blending components. Numerous catalysts including the various zeolite catalysts are useful in such processes. Heavy naphtha feedstock would also be a useful source of blending components. However, conventional zeolite catalysts are rapidly deactivated by sulfur, nitrogen, coke, and other contaminants which may be present in heavy naphtha feedstock.
U.S. Pat. No. 4,734,539 to Lawlor et al. discloses such a catalyst which is useful in some applications. However, the catalyst of Lawlor et al. is susceptible to sulfur deactivation and has a one dimensional pore system which leads to rapid deactivation by coke as well. U.S. Pat. No. 4,962,269 to LaPierre et al. also discloses a process for isomerization using zeolite catalyst. However, LaPierre et al. use Y or ZSM-20 zeolite, which is a specialty product (and therefore increases the cost of the process). LaPierre et al.'s process also leads to an undesirable increase in aromatics.
It is the primary object of the invention, therefore, to provide a process for hydroconversion of a heavy naphtha feedstock having a high content of sulfur and nitrogen contaminants so as to provide useful gasoline blending products.
It is a further object of the invention to provide a catalyst for hydroconversion processes which is not significantly deactivated by sulfur, nitrogen and coke.
It is a still further object of the invention to provide such a hydroconversion catalyst which provides significant levels of isomerization without increasing the output of aromatics.
It is another object of the invention to provide a process for preparing a catalyst in accordance with the invention.
Other objects and advantages will appear hereinbelow.